Hose clamps of a multiplicity of configurations are well known in the art. Generally, the clamps are comprised of a notched band, a housing connected to the band, and a worm screw in the housing that cooperates with the notches of the band. An example of a prior art hose-clamp is shown in FIG. 1 where it can be seen that rotation of the worm screw causes the diameter of the band to decrease about the object to be clamped.
A primary property of a worm drive clamp is the magnitude of the torque required to produce failure of the clamp. The usual failure of this type of clamp construction, when tested to destruction, is caused by the rotating screw acting frictionally upon the band and producing a lateral or side acting force. The lateral acting force in turn acts on the side of the housing and causes the housing to deform and open the connection between housing and band. This results in failure by allowing the notched band to lose its engagement with the screw threads.
Several prior art references disclose means for more securely connecting the housing to the band, such as U.S. Pat. No. 4,993,124 to Ouimet, and U.S. Pat. No. 4,473,928 to Johnson. Additionally, U.S. Pat. No. 4,257,149 to Sydendal recognizes the problem of lateral force deformation, and discloses a structure designed to avoid the problem.
The clamps disclosed in the prior art designed to avoid lateral force deformation necessarily utilize a "force fit" assembly process. For example, the Ouimet '124 patent discloses a housing with wings that help secure the housing to the band. Assembly of such a device first requires placement of the band within the housing. The wings, extending into the housing, are then bent into shape to secure the band. The worm screw cannot be placed in the housing prior to bending of the wings as access to the wings would otherwise be prevented.
The next step of the assembly process is to force fit the worm screw into the housing by threading the worm screw into the housing. Because of the helix angle of the worm screw, the screw enters the housing at an angle and strikes the interior of the housing. However, the housing in a standard clamp is resilient enough to allow the screw to continue to be threaded into place through the force fitting. None of these references, nor any of the prior art, however, discloses a structure for avoiding lateral force deformation in clamps of the configuration requiring insertion of the worm screw in the housing prior to attachment of the band to the housing: i.e., clamps that cannot be force fit.
One example of a clamp that cannot be force fit is a micro-clamp. Force fitting of the worm screw into the housing is not possible because the reduced size of the housing results in housings with increased stiffness that do not permit complete threading of the screw into place.
Due to the inherent nature of micro-clamps, a different assembly sequence is therefore required. The worm screw is placed inside of the housing before the band, thus blocking access to any of the prior art structures for avoiding lateral force deformation.
A second common example of a clamp that cannot be force fit is an assembly (either standard or micro) utilizing a screw thread of a root diameter larger than the screw bearing diameters in the housing. In such a case, the screw bearing diameters in the housing do not permit entry and threading of the screw into the housing. The industry's solution to this problem is to again place the worm screw inside of the housing, prior to insertion of the band. Thus, until now, micro-clamps and clamps utilizing root diameters larger than bearing diameters have continued to suffer from lateral force deformation and its accompanying problems.